In recent years, balloon catheters have been used for improving lesion affected areas (stenosed parts) generated in body lumens. A balloon catheter can include an elongate shaft portion, and a balloon, which is provided on the distal side of the shaft portion and is inflatable in the radial direction. After the balloon in a deflated state is brought to a target site in the body by way of a thin body lumen, the balloon is inflated, whereby the lesion affected area can be pushed wide open.
If a lesion affected area is forcibly pushed open, excessive proliferation of endothelial cells may occur, causing new stenosis (restenosis). In view of this, recently, drug eluting balloons wherein an outer surface of a balloon is coated with a drug for restraining stenosis have been used. The drug eluting balloon, by being inflated, is able to instantaneously release the drug contained in the coating on the outer surface thereof to the lesion affected area and transfer the drug to the living body tissue, thereby restraining restenosis.
A variety of methods have been proposed for coating a balloon with a drug. For instance, U.S. Patent Application Publication No. 2010/055294 describes a method in which a coating liquid containing a drug is supplied to a surface of a balloon while the coating quantity is being controlled and the balloon is being rotated and being moved in an axial direction, and the coating liquid is dried to form a coating layer containing the drug.